Alley Alley measured a meters. At the beginning and end are planted poplar. How many we must plant poplars to get the distance between the poplars 15 meters?

Decide The rectangle is divided into seven fields. On each box is to write just one of the numbers 1, 2 and 3. Mirek argue that it can be done so that the sum of the two numbers written next to each other was always different. Zuzana (Susan) instead argue that.